From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCHSET] blkcg: accumulated blkcg updates Date: Wed, 7 Mar 2012 16:06:33 -0800 Message-ID: <20120308000633.GH30676@google.com> References: <1329875223-5102-1-git-send-email-tj@kernel.org> <20120305210726.GC1263@google.com> <20120305210836.GD1263@google.com> <20120306150709.GA32148@redhat.com> <20120306162455.GB32148@redhat.com> <20120306183942.GC32148@redhat.com> <20120306190211.GD32148@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20120306190211.GD32148@redhat.com> Sender: linux-kernel-owner@vger.kernel.org To: Vivek Goyal Cc: axboe@kernel.dk, ctalbott@google.com, rni@google.com, linux-kernel@vger.kernel.org, dm-devel@redhat.com List-Id: dm-devel.ids Hello, On Tue, Mar 06, 2012 at 02:02:11PM -0500, Vivek Goyal wrote: > Ok, found it. Basically we have not initialized the q->queue_head during > queue creation. Hence we end up thinking that q->queue_head is not empty. > > So following fixed the issue for me. I still don't understand the special > cased code (q->queue_head is not empty but don't kick queue). It was mainly to avoid adding a new requirement as we didn't use to require queue_head to be empty on exit. I didn't realize we weren't initializing queue_head from alloc. Jens folded your fix into the original patch, so we might not need the special case anymore. I'll post fix for the RCU deref warning shortly. Thanks. -- tejun